The present invention relates generally to valves and, more particularly, to a valve that provides a rotary-to-linear assembly to control linear movement of a closure element in response to rotation of a valve stem.
Means for operating the closure element of a valve to thereby control flow through the valve are well known in the prior art. A unique type of rack and pinion means for operating the closure element is disclosed in the parent to this application that solves many problems of prior art valves. However, in some cases, it would be desirable to provide a highly reliable means for operating a rotary to linear valve that is easily adaptable to various valve sizes and which may be manufactured at relatively low cost, as described herein.
Generally, a valve is most commonly a mechanical device that regulates the flow of gases, liquids, or loose materials by blocking and uncovering openings. Typically a valve is used to regulate or control fluid flowing across a device or juncture. A valve may be positioned such that the flow across the openings is wide open, completely closed or any position in between. In fact, an important development in valves was the invention of a valve that could be selectively opened in a plurality of positions from wide open to closed.
This variety of valves has been used for controlling the throttle of a flow of fluid. Most throttle control valves are operated by a sliding stem or a rotary action. These sliding stem or rotary valves have been actuated by mechanical, electrical or pneumatic means. However, the majority of presently available rotary valves employ many components. These many components are often subject to time consuming, labor intensive and expensive repair. Examples of some of the components are rotary link arms, rotary shafts, and diaphragm rods.
Further, and common in the art is a right angle gear or a rack and pinion gear. These gears have been used for a long time in the prior art for purported conversion of a rotational force into a linear force. Prior art devices such as U.S. Pat. Nos. 3,265,173; 4,018,097; 4,046,210; 4,050,534; 4,263,834; and 4,651,587 utilize a pinion gear for right angle drive trains and for heavy duty drive axles. These different gears are configured for different gear ratios and may have different number of teeth for different required torque. However, these gears do not truly convert a rotational motion into a linear motion.
Other examples of the prior art include U.S. Pat. No. 4,611,630 which discloses a choke valve with an internal cylinder and an external sleeve. The sleeve is controlled by a hydraulic control mechanism for opening and closing the ports. However, the valve is not opened and closed with the translation of rotational motion to linear motion. A drive shaft is fixed with a pin that is off center and is positioned within a slot of a carrier plate. When the drive shaft is rotated, the carrier plate is rotatably moved back and forth.
U.S. Pat. No. 5,623,966 discloses a choke for controlling the flow of fluid through a body having a fluid outlet. A rotatable handle is attached to a rotatable inner sleeve that moves from a position obscuring an opening to a position not obscuring the opening. The valve does not translate rotary motion to linear motion.
Accordingly the art does not have a valve that translates a rotational force into a linear force for selective operation of a valve.
The present invention provides a valve for controlling fluid flow. The valve comprises one or more elements such as, for example only, a valve housing that is substantially tubular and comprises a tubular wall. The tubular wall defines a fluid flow path within the tubular wall and the valve housing defines an inlet for receiving the fluid into the fluid flow path. The valve housing defines an outlet through which the fluid exits from the fluid flow path of the valve housing. The valve housing also defines a bonnet aperture within the tubular wall. A bonnet is sealingly securable to the bonnet aperture and the bonnet defines a stem shaft aperture therethrough. A rotatable stem shaft extends through the stem shaft aperture in the bonnet. The rotatable stem shaft has a stem shaft axis of rotation. At least one stem shaft seal may preferably be utilized between the rotatable stem shaft and the bonnet if necessary to prevent fluid leakage. A stem drive element for the rotatable stem shaft is mounted with respect to the stem shaft seal such that the stem drive is exposed to the fluid pressure within the valve housing. A tubular cage is mounted within the valve housing. The tubular cage has a tubular axis and defines one or more holes therein. The bonnet aperture is positioned radially outwardly with respect to the tubular axis of the tubular cage. The rotatable stem shaft is oriented with respect to the tubular cage element such that the stem shaft axis of rotation intersects with the tubular cage element. A sleeve slidably is mounted with respect to the tubular cage. The sleeve may be moveable between a first position and a second position for covering and uncovering the one or more holes to thereby control the fluid flow through the valve. An interconnection is provided between the stem drive element and the sleeve such that the sleeve is moveable between a first position and a second position relative to the tubular cage in response to rotation of the stem shaft.
The valve may further comprise a tubular cage and a sleeve having in combination a diameter, the bonnet aperture having a bonnet aperture diameter greater than the diameter of the tubular cage and the sleeve in combination. In one preferred embodiment, the cage has a closed end and an open end. The closed end of the cage may be substantially hemispherical.
The sleeve drive element may define a first channel therein. In a preferred embodiment, the first channel comprises a first side and a second side such that the first side and the second side are substantially parallel with each other. The sleeve may also define a second channel therein.
The valve may further comprise a first interconnection member for insertion in the first channel and/or a second interconnection member for insertion into the second channel.
In another embodiment, a valve is provided that comprises one or more elements such as, for example, a rotatable stem shaft that extends through an aperture in the valve housing, at least one actuator shaft seal around the rotatable stem shaft, a stem drive element for the rotatable stem shaft drive shaft, a closure element slidably mounted for linear movement with respect to valve housing to thereby control the fluid flow through the valve, and a plurality of interconnection members for interconnecting the rotatable shaft and the closure element wherein the plurality of interconnection members are slidably mounted to at least one of the stem drive element or the closure element. In one embodiment, the valve further comprises a tubular cage defining apertures therein which are coverable and uncoverable by the closure element. Preferably, at least one of the stem drive element or the closure element defines a first channel and/or a second channel. The plurality of interconnection members each have a plurality of linear connections, and the plurality of extensions are mounted the first channel and/or the second channel. The plurality of extensions are mounted for linear movement within in the first channel and/or the second channel. The first channel and the second channel are preferably oriented in different directions with respect to each other. In a preferred embodiment, the plurality of interconnection members have a rotatable
connection at one end thereof and a slidable connection at an opposite end thereof.
A method is provided for assembling a valve which comprises one or more steps such as, for instance, providing a valve body with an inlet and an outlet and a bonnet port, attaching a sleeve to a cage such that the sleeve is slidable in a linear direction to cover and uncover apertures on the cage, inserting the cage and the sliding sleeve into the valve body through the bonnet port, mounting a bonnet to the bonnet port, sealing a rotatable shaft which extends through the bonnet with a shaft seal to prevent fluid leakage through the bonnet, providing a stem drive element on the stem shaft, and interconnecting the stem drive element and the sleeve with a plurality of interconnection members. The plurality of interconnection members being linearly slidable with respect to one of the stem drive element and sleeve.
The method may further comprise providing a first channel in at least one of the stem drive element or the sleeve and inserting at least one of the plurality of interconnection members into the first channel. The method may further comprise providing a second channel in at least one of the stem drive element or the sleeve, and/or inserting at least one of the plurality of interconnection members into the second channel.
In a preferred embodiment, the method of claim may further comprise providing that each of the interconnection members has a rotatable connection on one end and a slidable connection on an opposite end thereof, and/or providing a plurality of channels on at least one of the stem drive and the sleeve for receiving the slidable connection on the plurality of interconnection members, and/or providing a plurality of holes on at least one of the stem drive and the sleeve for receiving the rotatable connection on the plurality of interconnection members.